Chemical material metering devices are used to meter chemicals, such as granular insecticides or herbicides, at an application rate recommended by the chemical supplier. Typically, a chemical storage hopper carries a supply of material that is fed by gravity into a metering device located at the bottom of the storage hopper.
Conventional metering devices include a feed wheel or agitator that is disposed to rotate over a metering orifice to aid in feeding material through the orifice. Rotation of the feed wheel provides for an even flow of material by agitating the material in the vicinity of the orifice. This agitation prevents bridging or caking that might otherwise occur and cause a blockage of the orifice and an interruption in the flow of material.
Chemical metering devices are used to apply a wide variety of chemicals. These chemicals use a variety of carriers for the active ingredient including a clay material and a sand material. As compared to chemicals using a sand carrier, chemicals having a clay carrier require a greater clearance between the feed wheel and the metering orifice to achieve the optimum agitation and flow characteristics.
A known method of providing for varying clearance to achieve optimum performance of a metering device with varying chemicals is to provide separate feed wheels of different size. This solution to the problem requires the operator to maintain an inventory of alternate feed wheels, and requires considerable operator time to effect the change.
Those concerned with these and other problems recognize the need for an improved material metering device.